Leitch Pass-Through Implementation Notes

Leitch Pass-Through protocol for router control is supported in Helm, RouteMaster and RouteMaster VR.

Originally developed by Leitch Technology in 1999, the protocol is used by Harris and Imagine Communications routers. Other manufacturers like For-A also use variants of the protocol, with custom extensions. Modern Harris/Imaging routers use the more extensive Harris LRC protocol.

RouteMaster uses the protocol for both outgoing and incoming connections, allowing third-party systems using Pass-Through to control RouteMaster.  Helm uses it for outgoing connections to control routers.

Limitations

The standard Pass-Through protocol does not give access to mnemonics for router sources and destinations. Also, there is no way to query the Lock status of a destination.

FOR-A MFR-4000 series

The MFR-4000 series routers offer an extended version of the protocol which they refer to as “Crosspoint Remote Control 2”, This supports retrieval of source and destination names from the router. Helm and RouteMaster use this extension if the UseRouterNames property below is set to true.

The router must be configured via the web UI to enable the “Crosspoint Remote Control 2” protocol. Setting the Username and Password properties is also required

Use over TCP/IP

Originally designed as an RS-422 serial protocol, Pass-Through can also be used over TCP/IP. There is no standard port number for this.

Supported and Required Commands

This table details the commands used for outgoing connections, and the commands supported for incoming connections.

Special Properties

For outgoing connections, the following properties can be set directly in Helm Designer, or in the RouteMaster configuration file.